BDNF and autism: Conversely, the levels of pro-BDNF, FGF-2, and LIF were found to be increased in autism sera compared to control (Fig. 2A and B; pro-BDNF, Student’s t-test, p = 0.0043; LIF, Student’s t-test, p = 0.0216; FGF-2, Student’s t-test, p = 0.0194).